What is Whois?
Wikipedia Article Describing WHOIS
| WHOIS (pronounced "who is"; not an acronym) is a query/response protocol which is widely used for querying an official database in order to determine the owner of a domain name, an IP address, or an autonomous system number on the Internet. WHOIS lookups were traditionally made using a command line interface, but a number of simplified web-based tools now exist for looking up domain ownership details from different databases. Web-based WHOIS clients still rely on the WHOIS protocol to connect to a WHOIS server and do lookups, and command-line WHOIS clients are still quite widely used by system administrators. WHOIS normally runs on TCP port 43. |
Whois can be used to check the availability of a domain, find contact information for a domain owner, and even determine who owns that IP that has been slamming your server! I've written two PHP functions, one for WHOIS, and one for IPWHOIS. You can find the functions here:
http://neranjara.org/article/title/PHP_WHOIS_and_IPWHOIS_functions
You can see these scripts in action here:
http://neranjara.org/tools/whois
http://neranjara.org/tools/ipwhois
